The aims of this proposal are to identify the structural and developmental requirements involved in the spatial regulation of signal transduction proteins in C. crescentus. Many signal transduction proteins, including those we propose to investigate in C. crescentus, are essential for bacterial growth or pathogenicity. As such, signal transduction proteins, or proteins that regulate their activities, are appropriate targets for antibiotics, and therefore, they have significant research value. The research proposed here will utilize site directed mutagenesis and Gfp reporter fusions to examine specifically what parts of various signal transduction proteins are required for normal localization. The functional activity of mutant proteins that fail to localize will be examined, and the relative importance of intracellular localization in cell growth and differentiation will be assessed. [unreadable] [unreadable]